Cushioning device



Nov. 12, 1946. 1.. D. FREEMAN 2,410,933

1 CUSHIONING DEVICE Filed Nov. 24, 1945 s 5 4 4 34 Z5 4 Z8 "Z9 H INVENTOR. lewzsfi'eeman to prevent more or less injury'to the lading in Patented Nov. 12, 1946 "UNITED STATES PATIENT OFFICE CUSHIONING DEVICE 7 Lewis D. Freeman, Richmond, Va. Application November 24, 1943, Serial No. 511,569

Thisinvention relates to cushioning devices, and more particularly to draft gears for railway cars and the like.

One of the objects of the invention is the provision of a new and improved cushioning device having novel means for initially resiliently cushioning a compressive force applied to the device, and for frictionally cushioning the final compressive movement thereof.

Another object of the invention is the provision of a new and improved draft gear having one type of means for cushioning the compression of the gear during a portion of its compressive movement, and a different type during the remaining portion of its compressive movement,

the construction being such that the one movement gradually and imperceptibly merges into the other.

Another object of the invention is the provision of a new and improved cushioning device or shock absorber that is simple and rugged in construction, efiicient in operation, composed of few moving parts, and that may be manufactured and assembled at a minimum of cost.

Other and further objects and advantages of the invention will appear from the following description, taken in connection with the accompanying drawing in which Fig. 1 is a longitudinal section of the device on the broken line l--| of Fig. 2; 1

Fig. 2 is a section on the line 22 of Fig; 1;

Fig. 3 is an end view of the wedge member; and

Fig. 4 is a section on the line 44 of Fig. 1.

Draft gears or cushioning devices for railway cars and the like must have the capacity for absorbing shocks incident to maximum loads, and 'hence for light loads, or partial loads, these cushioning devices are often not sufficiently resilient rough handling of the cars. v

The present invention seeks to remedy this difficulty by the provision of resilient mechanism that is so constructed that during initial'movement of the cushioning device or shock absorber the shocks incident to switching and sudden stopping and starting of the car will be resisted initially by resilient means alone, and the final movement willbe resisted by friction mechanism.

Referring now to the drawing, the reference character In "designates thecushioning device or draft gear, comprising a casing I I which is hollow and open at one end, as at l2, and closed at the other, as at 13. The interior walls of the casing are angular in cross-section, as shown at M in- Claims. (Cl. 213-24) 2 Fi 2. The outer walls may, if desired, be sim-'- ilarly'formed.

Preferably, though not necessarily, the walls are hexagonal. The upper and bottom walls of the casing are flat, as shown at l5 and. I6. Suitable reinforcing members are provided for the sides of the casing, and these members, as shown at I! and I8, are T-shape and integral with or rigidly attached to the vertex of the side angle formed by the sides, and extend laterally therefrom. The inner and outer ends of the reinforcing members [1, l8, and the casing are provided with strengthening flanges or webs 19, 2|, and 22, 23, at each end of the casing. The inner walls of the open end of the casing are preferably thickened, as at- 24, which constitutes a reinforcement against bursting strains for this portion of the casing within which the wedge mechanism operates, as will presently appear.

Mounted within the casing II is the wedge mechanism, which comprises friction shoes 25 each-of which is provided with outer angular friction faces 20 and 30, Fig. 2, that engage two of the inner faces 14 of the casing. There are three of these wedges arranged apart. Since they are alike only one need be described. 7

These shoes are each provided at their outer ends with'a single inclined friction face 26, and at their inner ends with an inclined friction face 21. Mounted inwardlyof the wedge members 25 is a spring seat 23, having "three outer inclined or wedge faces 29, one for each of the wedge faces 2'! of the wedge members 25. One or more resilient elements, such as the springs 31,32,

are adapted to engage the inner face of the spring 'seat 28, as shown more clearly in Fig. 1 of the drawing. A wedge member 33, having three wedging faces 34', Fig. 3, engaging the wedging faces 26 of the corresponding wedge members 25, is provided. This wedge member extends member 4|, is employed for this purpose. These depressions are of sufficient depth to accommodate the bolt 36 during the compression of the gear. The spring abutment member 4| its body portion 39 extending inwardly between the wedges 25, and is provided at its outer end with a flanged head 42 against which a spring 43 abuts. This spring has its outer end seated in a recess 44 in the follower 35, which positions said spring. The wedge 33 is hollow at its outer end for receiving the head 42 and the inner end of the spring 43, as clearly shown in Fig. 1 of the drawing.

In order to properly hold the wedge member 33 in engagement with the friction shoes 25 when the spring is in release position, a resilient member, such as a rubber ring 45, is mounted on the inwardly extending circular body portion 39 of the spring abutment member 4|, and in engagement with the inner end of the wedge member 33 and with the head and flange portion 42 of the abutment member 4|.

The follower 35 is limited in its outer movement and held in position by bolts 41, 48. The bolt 41 extends through the web l9 on one side of the rib of the T member I1, and the bolt 48 at the opposite side of the casing extends on the opposite side of the web portion of the T member I8, so as to properly position the follower 35 and prevent it from tilting. It is apparent that the casing II and the follower 35 are two normally spaced members that are movable toward each other in response to the forces that are to be cushioned.

In assembling the device just sufficient tension is put on the spring 43 by the bolts 41, 48, to hold the parts in set-up position. The springs 3|, 32, of the wedging mechanism are placed under initial tension, which is approximately equal to the tension of the spring 43 when the same is compressed to its maximum extent, so that when force is applied to the follower 35 tending to compress the gearthe spring 43 will permit the follower to approach the wedge 33 without moving it inwardly until the follower engages the end of the Wedge 33. During the further compression or" the gear the follower 35 will force the wedge member 33 inwardly, and the springs 3|, 32, operating through the wedging faces of the spring seat 28, will force the wedges into frictional contact with the inner sides of the casing, whereby the inner movement of the wedge 33 will be frictionally resisted by the friction shoes, as well as by the compressive resistance of the springs 3|, 32.

It will thus be seen that by placing the springs 3| and 32 under initial compression substantially equal to that of the spring 43, when the follower seats on the Wedge member 33, that the shocks of pull and buff will be resisted and partially absorbed entirely by the spring 43, and consequently the shocks will be greatly cushioned for all loads. After the follower seats on the wedge member 33, as a result of the more severe shocks, the final compressive movement of the gear will absorb these shocks by the friction devices plus the resistance to compression of the springs 3| and 32. It will also be appreciated that the transition from the initial resilient resistance to compression to the final frictional resistance to compression will be gradual and imperceptible.

It is thought from the foregoing, taken in connection with the accompanying drawing, that the construction and operation of my device will be apparent to those skilled in the art, and that changes in size, shape, proportion and detail may be made without departing from the spirit and scope of the appended claims I claim as my invention:

1. In a cushioning device, a casing having interior angular walls in cross-section and having an open and closed end, friction shoes each engaging two of said interior walls, each shoe having an inclined wedging face at its inner and at its outer end, a spring plate having inclined faces engaging the inclined inner faces of said shoes, resilient means under initial compression between said spring plate and the closed end of said casing, a wedge member having wedging faces engaging the outer wedging faces of said shoes and extending outward beyond the open end of said casing, a follower, and means including a resilient element between said follower and said spring plate whereby said last-named means initially resists the compression of said device.

2. In a cushioning device, a casing, shoes positioned within said casing for inward travel in contact with the casing, means including spring means for resisting said inward travel of the shoes, wedge means cooperative with said sp means for engaging said shoes to press the shoes against said casing during said travel, a follower for movement against said wedge means to compress said spring means only in response to the final compressive movement only of said device, and additional spring means for resisting the initial compression of said device prior to said final compressive movement.

3. In a draft gear, a casing, a Wedge mechanism for resisting the final compressive movement of said gear, spring means to apply pressure to said wedge mechanism, means to prevent said spring means and said wedge mechanism from resistin the initial compressive movement of said gear, and resilient means cooperating with said spring means for resisting the initial compressive movement of said gear. I y

4. In a draft gear, a casing having an open and a closed end, friction shoes frictionally engaging the inner surface of said casing, springs for resisting the movement of said shoes toward the closed end of the casing, a wedge member engaging said shoes, a follower, and spring means for resisting the movement of said follower toward said casing, said spring means cooperating with all of said springs constituting the sole means for resisting the inward movement of said follower until said follower seats on said wedge member. i

5. In a cushioning device, a, casing, friction shoes engaging said casing, means including a plurality of springs for resisting the inward movement of said shoes, a wedge member engaging said shoes for forcing the same radially outwardly, said wedge member extending outwardly of said casing, a spring abutment member extending through said wedge member and held against inward movement by said springs, a follower, resilient means between said follower and abutment member for normally holding said follower spaced from said abutment member, and means for holding said first-named means under such compression that upon the compression of said cushioning device the pressure of said first=named means will be approximately equalized on opposite ends of said abutment member approximately at the time said follower engages said wedge member, whereby the initial compressive movement of said cushioning device will be yieldingly resisted solely by said last-named resilient means. i

6. A cushioning device comprising friction an w'edging mechanism and cooperating springs and spring resistance means in series, and means for causing said spring resistance alone to yield during the initial compression of said gear, and said friction and wedging mechanism and said springs alone to yield during the final compressive movement of said device.

7. In a device of the character described to cushion forces, two normally spaced members movable toward each other in response to said forces, relatively weak yielding means positioned between said members to resist relative movement of the two members toward each other over an initial range of movement, relatively strong yielding means positioned between said two members to resist relative movement of the two members toward each other over an additional range of movement, means responsive to relative movement of the two members toward each other to prevent yield of said relative weak means over said additional range of movement, means to confine said relatively Strong yielding means under compression thereby to prevent said relatively strong means from resisting relative movement of said two members over said initial range, and friction means adapted to receive pressure from said relatively strong yielding means to resist relative movement of said two means toward each other over said additional range.

8. In a device of the character described to cushion forces, two normally spaced members movable toward each other in response to said forces, relatively weak yielding means positioned between said members to resist relative movement of the two members toward each other over an initial range of movement, relatively strong yielding means positioned between said two members to resist relative movement of thetwo members toward each other over an additional range of movement, means responsive to relative movement of the two members toward each other to prevent yield of said relative weak means over said additional range of movement, means to confine said relatively strong yielding means under compression thereby to prevent said relatively strong means from resisting relative movement of said two members over said initial range, and Wedge means to transmit said forces to said relatively strong yielding means when the relative movement of said two members enters said additional range of movement and to frictionally resist the relative movement in said additional range in response to the resistance of the relatively strong yielding means.

9. A device of the character described to cushion forces as set forth in claim 7, in which the maximum resistance to relative movement of the two members offered by said relatively weak Yielding means is on the same order of magnitude as the minimum resistance to the relative movement offered by said relatively strong yielding means.

10. In a device of the character described to cushion forces, two normally spaced members to receive said forces for relative movement toward each other in response to the forces, a first spring means, a spring seat cooperative with one of said members to confine said spring means, means acting between said spring seat and said one member to limit the spacing therebetween thereby to hold said spring means under compression and to prevent said spring means from resisting relative movement of said members toward each I other over an initial range of relative movement, a second spring means acting between said spring seat and the other of said members to resist relative movement of said two members toward each other over an additional range of movement, said second spring means being limited in yielding movement substantially to said initial range of movement, and a wedge mechanism acting between said spring seat and said other member in response to relative movement of the two members in said additional range, said wedge mechanism being adapted to transmit a portion of said forces to said first spring means and to frictionally resist said forces in said additional range of movement.

LEWIS D, FREEMAN, 

